為方便河流實務工作者掌握各地的河性,許多國家以劃設流域區(River Basin District, RBD)的做法,作為流域管理的基本單元。本研究將臺灣本島的地形、地質、水文條件類似的相鄰流域,合併為13個流域區。此外,為掌握沖積河川縱向地形變化,綜合分析河床坡降、谷壁受限情況、河道平面形態與改道特性、等高線排列形態、地質組成等因素,提出山區、沖積河谷、沖積扇、平原等四種地形的縱向分段準則,並應用這些準則,為26條中央管河川主流,訂出明確的地形分段點。依據縱向地形分段的排列模式,可進一步將臺灣河川歸納為四個類群:蜿蜒河、獨流溪、辮狀河與失能河。如此可反映臺灣地形地質條件下河流的發育狀況,且與流域區有大致的對應關係。應用此類群區分原則,本研究為26條中央管河川及92條縣市管河川指認河川類群。臺灣河川流域區、地形分段與類群的建構與分析,對於河川治理與管理、災害風險評估、國土規劃等工作都有實用價值。
To facilitate watershed management in Taiwan, a procedure combining neighboring basins with similar morphological, geological, and hydrological conditions into 13 river basin districts (RBDs) was developed in this study. A mechanical approach that considers factors such as channel slope, valley confinement, and geological features was developed to divide streams into four longitudinal segments, namely mountains, alluvial valleys, alluvial fans, and plains. This study further classified streams in Taiwan into four morphological groups, namely meandering rivers, independent streams, braided rivers, and underfit streams, each with a corresponding longitudinal arrangement of river segments that represented a different landscape evolution. In total, 26 rivers and 92 streams managed by central and local governments, respectively, were classified into morphological groups, and streams in the same RBD could often be assigned to the same group. The analytical framework of this study can be applied to river management and planning to advance understanding of stream characteristics.